Apparatus for providing spectrum analyses using photodetection devices, such apparatus generally being referred to as spectrophotometers, have long been used to analyze fluid samples by comparing the spectral characteristics of unknown fluid samples, over selected frequency bands, with the spectral characteristics of known standard fluid samples. One apparatus which has been available and has been successfully used for such purpose, for example, is the Nicolet Model 7199 Fourier Transform Infrared Spectrophotometer made and sold by Nicolet Instrument Corporation of Madison, Wisconsin, which spectrophotometer utilizes Fourier transform techniques for analyzing materials in the infrared portion of the spectrum.
In using such an instrument for analysis of fluids a container is normally filled manually with said fluid, whether of a blank solution, a known standard solution, or an unknown fluid sample solution, to be analyzed. The fluid is then appropriately scanned to provide scanned data with respect to its spectral characteristics and the scanned data is then suitably processed using Fourier transform techniques, as would be well known to those in the art. During the filling of the container the fluid sample is generally exposed to the atmosphere. When the analysis of a particular fluid sample has been completed, the container must be removed, rinsed clean and dried before being filled with another fluid solution and replaced in the apparatus for analysis of the next fluid sample.
Such a technique not only is physically cumbersome but requires the presence of an operator for performing each container loading, cleaning, refilling and replacement operation. Further, the time required to perform an analysis of a large number of different fluid samples becomes undesirably excessive and, since the user's presence is required throughout the overall operation, the user is not free to perform other tasks. Moreover, the exposure to the atmosphere of the fluid samples during the filling and scanning process causes fluid evaporation to occur, particularly when the fluid is relatively highly volatile in nature.
It is desirable then that a technique be devised for performing a spectrophotometric analysis of a relatively large number of different fluid samples in an automated fashion so as to decrease the overall time involved therefor and to free up the user for other tasks while the consecutive sampling and analyses of the samples are being performed, as well as to free up the instrument itself for other analytic tasks. It is further desirable that such automated technique be arranged to avoid the necessity for removing the container in which the fluid sample is retained so that accuracy and precision are increased and instrument purging thereof remains constant. It is further desirable that the fluid samples be handled so that little or no evaporation thereof occurs.